The technical field of the present invention relates to vehicle windshields, and more particularly windshields that are removable for emergency egress.
In certain vehicle accidents it may be difficult, impossible, or unsafe to exit from the doors of the vehicle. In a typical vehicle roll-over, for example, one door is under the cab and the other door facing upward. When the vehicle is a heavy truck, or in particular an armored vehicle, the weight of the door makes it difficult to lift open and hold open, both for an emergency responder and more so for a vehicle occupant attempting this from the inside of the vehicle cab. Egress through the windshield frame may be the fastest and safest alternative.
For this reason the windshields in certain large vehicles or trucks, and in particular ballistic resistant windshields in certain military vehicles, are designed so that the windshield can be removed, either from inside or outside the vehicle, when exiting from the doors is difficult or unsafe. One such example of a removable ballistic resistant windshield is disclosed in U.S. Pat. No. 8,382,191 issued to BAE Systems of Santa Clara, Calif. The disclosed system uses two handle-operated cam locks, one lock on each side of the left and right windshield panels, to retain and release each panel. In order to release the windshield after a rollover, the passenger or rescuer must rotate both handles in the correct direction, and far enough to release the cam latches. The windshield panels must then be pushed outward with sufficient force to dislodge the windshield from the vehicle and cause it to fall away. However, due to the holding forces necessary to properly retain and seal the windshield, rotating the handles to release the windshield can be difficult, particularly for an injured vehicle occupant or under emergency conditions. In addition, because the windshields may be removed from outside the vehicle by simply rotating the outside handles, the vehicle cab is left effectively unlocked at all times and thus vulnerable to intrusion.